Coupling device for connecting prosthesis components by a self-locking press fit

ABSTRACT

A coupling device is for connecting prosthesis components by a self-locking press fit on an end, formed as a cone, of a first prosthesis component that is inserted in bone tissue. The coupling device has an outer coupling body with a socket having a conically tapering inner wall, and an expansion sleeve having a lateral surface forming a male taper and an operative forming a female tape. The expansion sleeve is mounted in the socket so as to be rotatable about the longitudinal axis thereof, and receives the cone. The expansion sleeve is expandable radially outwardly to form the self-locking press fit, such that the expansion sleeve widens radially when the cone is inserted into the expansion sleeve. As a result, the self-locking press fit between the cone of the first prosthesis component and the coupling device is established.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/979,035, filed May 14, 2018, which claims the benefit of and priorityfrom German Patent Application No. 10 201 7 004 911.4, filed May 16,2017 in the German Patent Office. Both the U.S. and the Germanapplications are incorporated herein by reference, in their entireties.

FIELD

The invention relates to a coupling device, by means of which componentsof a prosthesis can be clamped against one another by means of a coneconnection so as to form a self-locking press fit, and can thus beinterconnected. In particular, the invention relates to a couplingdevice for the cone connection between the hip-stem and the insertionhead of a hip endoprosthesis.

BACKGROUND

In particular in the field of hip endoprosthetics, the cone insertionconnection between the femoral head and the hip-stem has proven itselfas a stable self-locking clamped connection. Moreover, on account of theclamping properties thereof, cone insertion connections are also used inother prosthetics care systems.

However, problems arise in relation to renewing the cone insertionconnection when one of the prosthetics components of the prostheticssystem needs to be replaced.

For example, replacing the joint head is generally associated withaltering the ball socket. In such a case, in order not to have to alsoexplant the existing shaft and replace said shaft with a shaft thatcorresponds to the cone of the new joint head, adapter sleeves have beendeveloped, by means of which the new joint head can be securelyconnected, in situ, with the remaining shaft, by means of a coneinsertion connection.

A plurality of conical adapter sleeves is known from the prior art,which sleeves have been designed for various purposes.

DE 40 08 563 A1 discloses a cone insertion connection of this kind, inwhich a conical adapter is used as a coupling means between the jointhead and the shaft neck in order to be able to connect joint heads andshaft necks by means of a frictional connection, it being possible forthe joint and the shaft neck to be produced from different materials andto also have different conicities.

Pre-assembled adapters for cone insertion connections are known from CH676 922 A5 and WO 2005/012596 A1. Said latter document in additiondiscloses the production of a conical adapter of this kind frombiocompatible plastics materials.

It is also known that, after the joint head has been removed, thesurface a shaft cone no longer has the quality that allows it to bepushed onto a replacement head in a manner free of stressconcentrations. As a result of said stress concentrations, fractures andbreaks may occur in the joint head, which can in turn lead to renewedaltering of the replacement joint head.

This problem is addressed in DE 103 03 660 B4, which document specifiesan adapter for providing existing shafts with new joint heads, whichadapter ensures that the stresses are distributed uniformly over thecontact surface or are diverted at least into the upper region of thecone. For this purpose, the adapter comprises a groove that extendsupwards from the lower, wider face of said adapter, and the female taperof said adapter has a curved course.

DE 199 04 437 A1 describes a conical adapter that has particularelasticity and damping properties. In order to more uniformly divert thestress between the cone of the shaft and the ball head, the adapter isformed as a porous package. The disclosed design makes it possible toreplace damaged ball heads without it being necessary to remove theshaft, even if the state of the surface of the cone would no longerallow the ball heads to be placed on directly.

In order to compensate for winding errors in the cone on the prosthesisneck while at the same time increasing the useful life of theprosthesis, EP 2 459 124 B4 provides an adapter that, althoughfundamentally a conical molded body, nonetheless comprises resilient andbearing portions which divert the force into a defined region in thejoint head and thus relieve the load-bearing regions.

A problem in prostheses that bear a cone is that the cone geometries arenot standardized, and therefore the dimensions of the cones of differentmanufacturers may differ significantly from one another. Specificationssuch as “12/14 Euro cone” or “12/14 standard cone” likewise do notdenote a cone geometry that is subject to a standard and whichguarantees standardized dimensions irrespective of the manufacturer.

If the cone of the prosthesis is then additionally damaged or if thetolerances thereof are outside the standard deviation usual inproduction, it is no longer possible to ensure a secure and long-termstable cone insertion connection between the prosthesis components, evenwhen using a cone adapter.

SUMMARY

The object of the invention is therefore that of specifying an adaptersystem for a cone insertion connection between prosthesis components,which system produces a long-time stable and secure press fit betweenthe prosthesis components, even in the case of damaged cones or cones ofwhich the geometries are unknown or cannot be determined.

In order to achieve this object, a coupling device for connectingprosthesis components is specified, by means of which device it ispossible to produce a self-locking press fit on an end, formed as acone, of a first prosthesis component that is inserted in bone tissue,and which device comprises an outer coupling body having at least onesocket that has a conically tapering inner wall, and an expansion sleevehaving a lateral surface that forms a male taper and an operativesurface that forms a female taper.

In this case, the expansion sleeve is mounted in the socket in thecoupling body so as to be rotatable about the longitudinal axis thereof,and is designed for receiving the cone of the first prosthesiscomponent.

The coupling system is characterized in that the expansion sleeve isdesigned so as to be expandable radially outwardly in order to form theself-locking press fit, such that the expansion sleeve widens radiallywhen the cone of the first prosthesis component is inserted into theexpansion sleeve, as a result of which widening the self-locking pressfit between the cone of the first prosthesis component and the couplingdevice can be established.

When forming the self-locking press fit, a plurality of pairs ofsurfaces interact with one another in the coupling device according tothe invention.

In this case, the following pairs of surfaces are at least involved informing the press fit between the first prosthesis component and thecoupling device:

-   -   a) the cone surface of the first prosthesis component and the        operative surface of the female taper of the expansion sleeve,        and    -   b) the lateral surface of the expansion sleeve and the inner        wall of the socket.

In the case of coupling to a second prosthesis component, at least thefollowing pair of surfaces is additionally involved in a clampedconnection:

-   -   c) the outer surface of the conical outer contour of the        coupling body, and the inner surface of a conical inner contour        in a second prosthesis component.

Said latter embodiment relates in particular to a conical adapter thatis inserted between a joint heat and a shaft neck in a hipendoprosthesis, in order to fix the joint head on the shaft cone.

Further fields of application of a coupling device according to theinvention relates to connection elements that are designed to connectprosthesis components such as bone nails to one another or to shafts ofjoint prostheses.

In the design according to the invention, the structural proportions ofthe expansion sleeve relative to the socket are such that, when notclamped by the cone of the first prosthesis component (free state) theexpansion sleeve can rotate freely in the socket. For this purpose, themale taper of the expansion sleeve is advantageously slightly smallerthan the internal taper of the socket, such that there is clearancebetween the expansion sleeve and the socket.

Only when the cone of the first prosthesis component is inserted intothe female taper of the expansion sleeve does the expansion sleevewiden, as a result of which the sleeve is expanded and the lateralsurface thereof is pressed against the inner wall of the socket, andthus a selflocking press fit is formed.

A first prosthesis component is in particular a hip shaft or anintramedullary bone nail that comprises one or more conical connectionregions.

The advantage of the coupling device according to the invention comparedwith the prior art is that the coupling device can bridge flaws,deformations or tolerance deviations in cones, and can thus connect saidcones to replacement components, and therefore the prosthesis componentsthat are still securely located in the bone—and when deemed so bydoctors—can be left in situ. As a result, it is possible to avoidcomplete replacements, which is beneficial to the patient, and thestress caused by a more complex operation is reduced, which in turnreduces the recovery times and improves the recovery prospects.

It has also been found that, when using a coupling device according tothe invention, less force needs to be applied when joining theprosthesis components in order to achieve a long-time stableself-locking clamping effect between the prosthesis components.

In order to achieve the radial expandability required for the expansionsleeve to be widenable, the expansion sleeve preferably comprises atleast one slit that begins at an edge and extends in the longitudinaldirection of the expansion sleeve. In a particular embodiment, theexpansion sleeve has a continuous slot in the longitudinal direction,and therefore the expansion sleeve is formed as a split ring.

In order to achieve more uniform force distribution when forming thepress fit, in a further embodiment, slots that extend in thelongitudinal direction are formed peripherally in the expansion sleeve,which slots advantageously begin alternately at the edge of the widerend and at the edge of the narrower end, such that the expansion sleevehas a serpentine structure.

In order to increase the strength of the press fit, the conicity of thefemale taper of the expansion sleeve may be slightly smaller than theconicity of the cone of the first prosthesis component, as a result ofwhich the expansion sleeve is forcibly widened when the cone isinserted.

In a further embodiment, the expansion sleeve is pre-assembled in thesocket of the coupling body, and is secured, in the axial direction,from slipping out of the socket.

In a first alternative, a radially peripheral bead is formed on thelateral surface of the expansion sleeve in order to hold the expansionsleeve in the socket, which bead can be brought into engagement with aradially peripheral groove in the inner wall of the socket. Thegroove-bead engagement is designed such that the bead snaps into thegroove when the expansion sleeve is inserted, but without the socketclamping the expansion sleeve, i.e. the groove-bead engagement maintainsthe rotatability of the expansion sleeve about the longitudinal axisthereof.

In a second alternative, the expansion sleeve is held in the socket bymeans of a radially peripheral undercut being formed in the receivingopening of the socket, on which undercut the lower edge of the expansionsleeve, inserted into the socket on the inside of the socket, issupported. What is essential is that the undercut opening should belarger than the opening of the expansion sleeve female taper located inthis region, and that the undercut should surround the expansion sleeveonly in the outer edge region thereof. The inner edge region of theexpansion sleeve therefore projects over the edge of the undercut, andtherefore the undercut does not impede the insertion of the cone of thefirst prosthesis component into the female taper of the expansionsleeve.

A step-like and radially peripheral constriction is advantageouslyformed on the inner wall, in the head region of the socket opposite thereceiving opening, by means of which constriction the inserted expansionsleeve is held so as to be spaced apart from the head region of thesocket. A hole that is open to the surroundings is advantageously formedin the head region of the socket, through which hole air can escape whenthe cone of the first prosthesis component is introduced. In addition, acorresponding instrument can also be inserted via the hole, by means ofwhich instrument the coupling body can be pushed away from one of theprosthesis components.

In a first embodiment, the coupling body has a conical outer contourwhich can be brought into a self-locking press fit with a conical innercontour in a second prosthesis component. The external shape and thepurpose of said embodiment substantially corresponds to the knownconical adapters that are used to establish a self-locking press fitbetween a joint head and a shaft cone. In this embodiment, the jointhead is thus the second prosthesis component.

In a second embodiment, the coupling device comprises a cylindricalcoupling body, on each of the ends of which a socket comprising anexpansion sleeve mounted therein is formed. A coupling device of thiskind is suitable for clamping the conical end regions of two prosthesiscomponents together in a self-locking manner. By way of example, acoupling device of this kind is used in intramedullary elongation ofexisting hip shafts in the dorsal direction, using bone nails.

The cylindrical coupling body may be straight or curved or angled. Saidlatter designs are suitable for bridging the joint region in the angledposition when permanent or temporally limited arthrodesis is required.

The invention will be explained in greater detail in the following withreference to a plurality of embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1: shows a structure, by way of example, of a connection between ofprosthesis components, in which a first and a second prosthesiscomponent are interconnected by means of a coupling device according tothe invention,

FIG. 2a-c : show a first variant of an outer coupling body,

FIG. 3a-b : show a first variant of an expansion sleeve,

FIG. 4: shows a first variant of a coupling device assembled from anexpansion sleeve and a coupling body,

FIG. 5a-b : show a second variant of an outer coupling body,

FIG. 6a-c : show a second variant of an expansion sleeve,

FIG. 7: shows a second variant of a coupling device assembled from anexpansion sleeve and a coupling body, and

FIG. 8: shows an alternative embodiment of a coupling device comprisingtwo expansion sleeve inserts formed at the opposing ends of the couplingdevice.

DETAILED DESCRIPTION

FIG. 1 shows a structure, by way of example, of a prosthesis in which afirst prosthesis component 1 having a conical connection region 2, and asecond prosthesis component 19 having a conical female taper 21 arecoupled together by means of two self-locking press fits. The connectionbetween the prosthesis components 1 and 2 is established by a couplingdevice according to the invention that is assembled from an outercoupling body 3 having a conical outer contour 20 and an expansionsleeve 6 that is formed in a socket 4 and is slotted.

The conical expansion sleeve 6 is rotatably mounted in the conicalsocket 4 of the coupling body 3 and is secured, by means of the undercut17, from slipping out of the socket 4.

In order to produce the press fit between the first prosthesis component1 and the coupling device, the cone 2 of the first prosthesis component1 is pushed into the female taper 9 of the expansion sleeve 6, as aresult of which the expansion sleeve 6 is widened and the lateralsurface 8 thereof is pressed against the inner wall 5 of the socket 4,with the result that the cone 2 of the first prosthesis component 1 andthe coupling body 3 are clamped together.

The second press fit is formed when the second prosthesis component 19is placed onto the conical outer contour 20 of the coupling body 3, bymeans of the conical coupling body 3 being driven into a conicalreceptacle 21 of the second prosthesis component 19.

In FIG. 1, by way of example a cone 2 of a hip shaft is shown as thefirst prosthesis component 1 and the joint head to be pushed onto thecone 21 of the hip shaft is shown as the second prosthesis component 19of the prosthesis.

FIG. 2a-c show a first embodiment of an outer coupling body 3. Theexternal shape 20 of the coupling body 3 shown is conical and the outercontour of said body thus corresponds to the adapters that are known inhip endoprosthesis and are used to connect ball heads and hip shafts.The socket 4 formed in the interior of the adapter is also conical. Inthe case shown, the cone angle of the male taper contour 20 and of theinternal taper 22 are identical. The sizes of the cone angles may,however, also be different from one another.

The receiving opening 16 of the socket 4, in which opening a peripheralundercut 17 is formed, as a result of which undercut the receivingopening 16 has a cross-section that is narrowed relative to the adjacentregion of the socket 4, is located in the region of the wide end of thecoupling body 3. The undercut 17 is shown again in detail in FIG. 2 b.

A step-like and radially peripheral constriction 18 (FIG. 2c ) is formedin the head region of the socket 4, by means of which constriction theexpansion sleeve (not shown) is held so as to be spaced apart from thehead region of the socket 4. The hole 23 that is additionally located inthe head region of the socket 4 has a plurality of functions. Firstly,said hole allows air to escape when the cone of the first prosthesiscomponent is inserted, and additionally a corresponding instrument canbe inserted via the hole 23, by means of which instrument the couplingbody 3 can be pushed away from one of the prosthesis components.

FIGS. 3a and b show an expansion sleeve 6 that is compatible with thecoupling body 3 shown in FIG. 2a -c.

The expansion sleeve 6 shown has a male taper 7 having a lateral surface8 and a female taper 9 having an operative surface 10. In order toproduce radial expandability, the expansion sleeve 6 is slotted in thelongitudinal direction, slots 11.1, 11.2 extending in the longitudinaldirection being formed peripherally in the expansion sleeve 6, whichslots begin alternately at the edge 12 of the wider end and at the edge13 of the narrower end, such that the expansion sleeve 6 has aserpentine structure.

FIG. 4 shows an alternative of a coupling device, in which an expansionsleeve 6, as shown in FIGS. 3a and b , is inserted into the socket 4 ofa coupling body 3 in an embodiment according to FIG. 2a -c.

As a result of clearance being created between the lateral surface 8 ofthe male taper 7 and the inner wall 5 of the coupling body 3, theexpansion sleeve 6 is rotatably mounted in the socket 4 and secured, bythe undercut 17, from slipping out of the socket 4, the lower edge 12 ofthe expansion sleeve 6 being supported on the undercut 17 on the insideof the socket.

What is essential in this embodiment is that the undercut opening shouldbe larger than the in large cone opening of the female taper 9 of theexpansion sleeve 6, such that the undercut 17 surrounds the expansionsleeve 6 only in the outer edge region 12 thereof. The inner edge region12 of the expansion sleeve 6 therefore projects over the edge of theundercut 17 in the direction of the longitudinal axis of the couplingdevice, and therefore the undercut 17 does not impede the insertion of acone 2 of the first prosthesis component 2 (not shown) into the femaletaper 9 of the expansion sleeve 6.

At the head end of the socket 4, the constriction 18 prevents the upperedge 13 of the expansion sleeve 6 from striking the end region of thecoupling body 3.

FIGS. 5a and 5b show a second embodiment of an outer coupling body 3.The external shape 20 of the coupling body 3 shown is likewise conicaland, in this variant too, the outer contour of said body corresponds tothe adapters that are known in hip endoprosthesis and are used toconnect ball heads and hip shafts.

The socket 4 formed in the interior of the adapter-like coupling body 3is also conical. In the case shown, as in the variant described above,the cone angle of the male taper contour 20 and of the internal taper 22are identical. The sizes of the cone angles may, however, also bedifferent from one another in this embodiment too.

A radially peripheral groove 15 is formed in the inner wall 5 of thesocket 4, which groove can be brought into engagement with a radial bead14 on the lateral surface 8 of an expansion sleeve 6.

A step-like and radially peripheral construction 18 (FIG. 5b ) is againformed in the head region of the socket 4, by means of whichconstriction the expansion sleeve (not shown) is held so as to be spacedapart from the head region of the socket 4. In this case, too, the hole23 that is additionally located in the head region of the socket 4 hasthe functions of allowing air to escape when the cone of the firstprosthesis component is inserted, or of allowing a correspondinginstrument to be inserted via the hole 23 in order to push the couplingbody 3 away from one of the prosthesis components 1 and/or 19.

FIG. 6a-c show a conical expansion sleeve 6 that is compatible with acoupling body 3 according to the embodiment shown in FIGS. 5a and b.

The expansion sleeve 6 shown has a male taper 7 comprising a lateralsurface 8, and a female taper 9 comprising an operative surface 10, thecone angles of the male and female tapers being the same.

A radially peripheral bead 14 is formed on the lateral surface 8 of theexpansion sleeve 6, which bead can be brought into engagement with theradially peripheral groove 15 formed in the inner wall 5, in order tohold the expansion sleeve 6 in the socket 4 of the coupling body 3.

In order to be able to widen the expansion sleeve 6 in the radialdirection, said sleeve is slotted peripherally, in the longitudinaldirection, the slots 11.1 and 11.2 that extend in the longitudinaldirection beginning alternately at the edge 12 of the wider end and atthe edge 13 of the narrower end of the expansion sleeve 6, such thatsaid sleeve has a serpentine structure that is expandable. In this case,the slots 11.1 and 11.2 divide the radial bead 14 into portions in eachcase.

FIG. 7 shows the second alternative of a coupling device, in which theexpansion sleeve 6 according to FIG. 6a-c is inserted in the socket 4 ofa coupling body 3 as shown by way of example in FIG. 5a-b . Theexpansion sleeve 6 is movably mounted in the socket 4 and secured fromslipping out of the socket 4 by means of the bead 14 engaging in thegroove 15.

FIG. 8 shows an embodiment of a coupling device according to theinvention, which device can be used for coupling two prosthesiscomponents that each have at least one conical end region.

Prosthesis components of this kind are in particular bone nails andshafts of joint prostheses, and therefore a coupling device of this kindcan be used to elongate existing shafts in the dorsal direction forexample.

In order to elongate the shaft end of a hip shaft in the region of thefemur, the coupling device having the expansion sleeve mounted in theproximal socket is pushed onto the cone on the shaft end for example. Inorder to be connected to an intramedullary bone nail, the expansionsleeve mounted in the dorsally formed socket is pushed onto the cone ofthe bone nail, as a result of which the hip shaft and the bone nail areeach coupled together, on either side, in the longitudinal direction, bymeans of a self-locking press fit.

For this purpose, the coupling device shown in FIG. 8 comprises acylindrical coupling body 3 which is straight in this embodiment and oneach of the opposing ends of which a socket 4.1 and 4.2, respectively,comprising an expansion sleeve 6.1 and 6.2, respectively, mountedtherein is formed.

The combination of the expansion sleeve 6.1 and the socket 4.1 which isformed on the upper end of the coupling body 3 corresponds to anembodiment as described with reference to FIG. 4. The combination of theexpansion sleeve 6.2 and the socket 4.2 located on the opposing end ofthe coupling body 3 is a variant according to the description of FIG. 7.

LIST OF REFERENCE SIGNS

1 first prosthesis component

2 cone of the first prosthesis component

3 outer coupling body

4 socket

5 inner wall of the socket

6 expansion sleeve

7 male taper

8 lateral surface

9 female taper

10 operative surface

11 slot

12 edge at the wide cone end of the expansion sleeve

13 edge at the narrow cone end of the expansion sleeve

14 bead on the lateral surface of the expansion sleeve

15 groove in the inner wall of the socket

16 receiving opening

17 radially peripheral undercut

18 step-like and radially peripheral constriction

19 second prosthesis component

20 conical outer contour of the coupling device

21 conical inner contour in a second prosthesis component

22 internal taper (female taper of the socket)

23 hole, open to the surroundings, in the head region of the socket

What is claimed is:
 1. A device for coupling a first prosthesiscomponent to a second prosthesis component, the device comprising: anouter coupling body having a socket and a conical outer surfaceconfigured to contact and couple to the second prosthesis component; andan expansion sleeve disposed in the socket and configured to radiallyoutwardly expand as the first prosthesis component is received into theexpansion sleeve within the socket.
 2. The device according to claim 1,wherein the outer coupling body is configured to be inserted into thesecond prosthesis component.
 3. The device according to claim 1, whereinthe socket has an inner wall against which the expansion sleeve pressesas the expansion sleeve radially outwardly expands.
 4. The deviceaccording to claim 3, wherein the expansion sleeve is axially retainedin the socket and rotatable therein about a longitudinal axis alongwhich the socket extends.
 5. The device according to claim 4, whereinthe outer coupling body has an undercut radially inwardly extending intothe socket to axially retain the expansion sleeve in the socket.
 6. Thedevice according to claim 4, wherein the expansion sleeve is tapered andhas a narrow end and an opposite, wider end.
 7. The device according toclaim 6, wherein the narrow end has an edge and the wider end has anedge, and wherein the expansion sleeve has a first plurality of slotsthat extend from the edge of the narrow end toward the wider end and asecond plurality of slots that extend from the edge of the wider endtoward the narrow end.
 8. The device according to claim 7, wherein thefirst plurality of slots is interdigitated with the second plurality ofslots.
 9. The device according to claim 8, wherein the expansion sleevehas a serpentine structure.
 10. The device according to claim 6, whereinthe narrow end and the wider end both radially outwardly expand as thefirst prosthesis component is received into the expansion sleeve.
 11. Adevice for coupling prosthesis components, the device comprising: anouter coupling body having a socket; and an expansion sleeve axiallyretained in the socket and rotatable therein about a longitudinal axisalong which the socket extends; wherein the expansion sleeve isconfigured to radially outwardly expand as a first prosthesis componentis received into the expansion sleeve within the socket; wherein theexpansion sleeve has a first end and a second end, both of which arereceived within the socket.
 12. The device of claim 11, wherein thefirst and second ends of the expansion sleeve both radially outwardlyexpand as the first prosthesis component is received into the expansionsleeve.
 13. The device of claim 11, wherein the first end has an edgeand the second end has an edge, and wherein the expansion sleeve has afirst plurality of slots that extend from the edge of the first endtoward the second end and a second plurality of slots that extend fromthe edge of the second end toward the first end.
 14. The deviceaccording to claim 13, wherein the first plurality of slots isinterdigitated with the second plurality of slots.
 15. The device ofclaim 11, wherein the outer coupling body has an outer surfaceconfigured to contact and couple to a second prosthesis component. 16.The device of claim 11, wherein the expansion sleeve has a conical outersurface and the socket has a conical inner wall.
 17. The device of claim11, wherein the expansion sleeve has an outer surface with a beadradially outwardly extending therefrom, and the socket has an inner wallwith a peripheral groove that engages the bead to axially retain theexpansion sleeve in the socket.
 18. The device according to claim 11,wherein the outer coupling body has an undercut radially inwardlyextending into the socket to axially retain the expansion sleeve in thesocket.
 19. The device according to claim 11, wherein when the firstprosthesis component is not received in the expansion sleeve, aclearance exists between an outer surface of the expansion sleeve and aninner wall of the socket.
 20. A device for coupling a first prosthesiscomponent to a second prosthesis component, the device comprising: anouter coupling body having a socket and an outer surface configured tocontact and couple to the second prosthesis component; and an expansionsleeve disposed in the socket and configured to radially outwardlyexpand as the first prosthesis component is received into the expansionsleeve within the socket; wherein the socket has an inner wall againstwhich the expansion sleeve presses as the expansion sleeve radiallyoutwardly expands; wherein the expansion sleeve is axially retained inthe socket and rotatable therein about a longitudinal axis along whichthe socket extends; and wherein the expansion sleeve is tapered and hasa narrow end and an opposite, wider end, and the narrow end and thewider end both radially outwardly expand as the first prosthesiscomponent is received into the expansion sleeve.